A solar battery module has been configured by forming strings having solar battery cells electrically connected to one another through interconnectors, and connecting the strings between a glass substrate and a back surface cover member via sealing materials.
A base material used for the interconnector typically takes the form of a rectangular wire having a rectangular sectional shape. This rectangular wire is obtained by rolling a round wire into the rectangular sectional shape with a view to providing the interconnector with an area to be joined to the cells, and facilitating the manufacturing.
Unfortunately, the rectangular wire interconnector material is more expensive than the round wire as the working cost of the rectangular wire increases due to the rolling.
Even if the round wire is used, the round wire, which is circular in section, undesirably has its small area to be joined to an element electrode formed on a solar battery cell surface. For the round wire to have the same conductor sectional area as that of the rectangular wire, the diameter of the round wire should be large relative to the thickness of a rectangular wire. Increasing the thickness of the interconnector placed on and joined to the solar battery cell leads to an increase in residual thermal stress during the joining.
Patent Literature 1 discloses a technology for forming an element electrode on a solar battery cell surface into a circular hollow shape to provide the element electrode with an area to be joined to a round wire interconnector.